The present invention relates generally to rocking chairs and, more particularly, to a rocking chair having an extensible leg rest assembly and an improved latching mechanism operable for releasably retaining the chair on a rearwardly "tilted" position following extension of the leg rest assembly.
Most rocking chairs typically include an upholstered chair frame supported from a stationary base assembly in a manner permitting the chair frame to "rock" freely in forward and rearward movements with respect to the base assembly. In order to provide enhanced comfort and convenience, many rocking chairs also include a "reclinable" seat assembly and/or an "extensible" leg rest assembly. For example, combination platform rocking/reclining chairs, as disclosed in Applicant's U.S. Pat. Nos. 3,096,121 and 4,179,157, permit reclining movement of the seat assembly and actuation of the leg rest assembly independently of the conventional "rocking" action. The leg rest assembly is operably coupled to a drive mechanism for permitting the seat occupant to selectively move the leg rest assembly between its normally retracted (i.e., "stowed") and elevated (i.e., "extended") positions. The drive mechanism is manually-operated and includes a handle which when rotated by the seat occupant, causes concurrent rotation of a drive rod for extending or retracting the leg rest assembly.
As an additional comfort feature, a latching mechanism may also be provided for releasably retaining the chair frame in a rearwardly rocked or "tilted" position on the base assembly following extension of the leg rest assembly to its extended position. In this manner, normal "rocking" action of the rocking chair is inhibited until the leg rest assembly is returned to its normally "stowed" position. Applicant's above-mentioned U.S. Patents each disclose the use of a "one-way" pawl and ratchet type latching mechanism having a pawl member supported for pivotable movement from the base assembly and a toothed ratchet sector fixed to the chair frame. An elongated U-shaped spring link is used to couple the pawl member to a drive link fixed to the drive rod. Movement of the pawl member between positions of engagement and disengagement with the toothed sector is caused in response to movement of the leg rest assembly between its extended and retracted position respectively. More particularly, when the handle is slightly rotated for partially extending the leg rest assembly, concurrent rotation of the drive rod and the drive link causes the spring link to forcibly pivot the pawl member toward the ratchet sector until its locking tip is positioned in locked engagement with the teeth of the ratchet sector. Thereafter, continued rotation of the drive rod and drive link for completely extending the leg rest assembly causes "elastic" flexure of the elongated spring link for applying a compressive force on the pawl member. However, the magnitude of the compressive force exerted by flexure of the spring link can vary since the displacement between the drive rod and sequential ratchet points on the ratchet sector vary in response to rearward tilting movement of the chair frame. Therefore, the flexure of the elongated spring link must be sufficient to ensure that the compressive force exerted on the pawl member is sufficient to maintain locked engagement between the pawl member and the teeth of the ratchet sector throughout the entire range of rearward "tilting" movement of the chair frame.
While such conventional latching mechanisms have generally performed satisfactorily, they are inherently noisy due to the spring link exerting a large compressive force on the locking tip of the pawl member at it "ratchets" over the the ratchet sector upon rearward tilting movement of the chair frame. In addition, the cyclical flexural requirements of the spring link may lead to premature fatigue fallure which could possibly cause unintentional release of the chair frame from its rearwardly tilted position.